Contra-parallel Overview
Contra-parallel Overview
Contra-parallels occur when bodies mirror declinations across the celestial equator. Their effect is similar to an opposition but via declination.
🧮 Contra-Parallel — Definition & Arithmetic
Two bodies are contra-parallel when they have equal declination on opposite sides of the celestial equator (one north, one south): δ₁ ≈ −δ₂ within ≈ 1°. It is traditionally read like an opposition (see also declinational opposition).
Declination δ is angular distance north (+) or south (−) of the celestial equator. A planet’s declination follows from its ecliptic longitude λ and latitude β: sin δ = sin β · cos ε + cos β · sin ε · sin λ (ε ≈ 23.436°).
🌠 Vault Stars — Contra-Parallel Targets (J2000)
| Star | Declination J2000 | Reachable by Sun (|δ| ≤ 23°26′) | Reachable by Moon (|δ| ≤ 28°36′, major standstill) | Contra-parallel point (−δ) |
|---|---|---|---|---|
| Polaris | +89° 15′ 51″ | no | no | -89.26° |
| Thuban | +64° 22′ 33″ | no | no | -64.38° |
| Alderamin | +62° 35′ 08″ | no | no | -62.59° |
| Schedar | +56° 32′ 14″ | no | no | -56.54° |
| Phecda | +53° 41′ 41″ | no | no | -53.69° |
| Alcyoneus | +52° 24′ 10″ | no | no | -52.40° |
| Mirfak | +49° 51′ 40″ | no | no | -49.86° |
| Alkaid | +49° 18′ 48″ | no | no | -49.31° |
| Copula | +47° 11′ 43″ | no | no | -47.20° |
| Capella | +45° 59′ 53″ | no | no | -46.00° |
| Deneb Adige | +45° 16′ 49″ | no | no | -45.28° |
| Menkalinan | +44° 56′ 51″ | no | no | -44.95° |
| Almach | +42° 19′ 47″ | no | no | -42.33° |
| Andromeda Galaxy | +41° 16′ 07″ | no | no | -41.27° |
| Algol | +40° 57′ 20″ | no | no | -40.96° |
| Vega | +38° 47′ 01″ | no | no | -38.78° |
| Mirach | +35° 37′ 14″ | no | no | -35.62° |
| Dheneb | +33° 58′ 13″ | no | no | -33.97° |
| Sheliak | +33° 21′ 46″ | no | no | -33.36° |
| Castor | +31° 53′ 18″ | no | no | -31.89° |
| Alpheratz | +29° 05′ 26″ | no | no | -29.09° |
| El Nath | +28° 36′ 27″ | no | no | -28.61° |
| Pollux | +28° 01′ 34″ | no | yes | -28.03° |
| Albireo | +27° 57′ 35″ | no | yes | -27.96° |
| Alphecca | +26° 42′ 53″ | no | yes | -26.71° |
| Alcyone | +24° 06′ 18″ | no | yes | -24.11° |
| Algenubi | +23° 46′ 27″ | no | yes | -23.77° |
| Hamal | +23° 27′ 45″ | no | yes | -23.46° |
| Adhafera | +23° 25′ 02″ | yes | yes | -23.42° |
| Tejat Posterior | +22° 30′ 49″ | yes | yes | -22.51° |
| Tejat Prior | +22° 30′ 24″ | yes | yes | -22.51° |
| Wasat | +21° 58′ 56″ | yes | yes | -21.98° |
| Asellus Borealis | +21° 28′ 07″ | yes | yes | -21.47° |
| Al Hecka | +21° 08′ 33″ | yes | yes | -21.14° |
| Zosma | +20° 31′ 25″ | yes | yes | -20.52° |
| Praesepe | +19° 59′ 00″ | yes | yes | -19.98° |
| Arcturus | +19° 10′ 57″ | yes | yes | -19.18° |
| Ain | +19° 10′ 50″ | yes | yes | -19.18° |
| Asellus Australis | +18° 09′ 16″ | yes | yes | -18.15° |
| Al Jabhah | +16° 45′ 46″ | yes | yes | -16.76° |
| Aldebaran | +16° 30′ 33″ | yes | yes | -16.51° |
| Alhena | +16° 23′ 57″ | yes | yes | -16.40° |
| Sualocin | +15° 54′ 43″ | yes | yes | -15.91° |
| Al Pherg | +15° 20′ 45″ | yes | yes | -15.35° |
| Markab | +15° 12′ 19″ | yes | yes | -15.21° |
| Algenib | +15° 11′ 01″ | yes | yes | -15.18° |
| Denebola | +14° 34′ 19″ | yes | yes | -14.57° |
| Rasalgethi | +14° 23′ 25″ | yes | yes | -14.39° |
| Ras Alhague | +12° 33′ 36″ | yes | yes | -12.56° |
| Rasalhague | +12° 33′ 36″ | yes | yes | -12.56° |
| Regulus | +11° 58′ 02″ | yes | yes | -11.97° |
| Acubens | +11° 51′ 28″ | yes | yes | -11.86° |
| Tarazed | +10° 36′ 48″ | yes | yes | -10.61° |
| Enif | +9° 52′ 30″ | yes | yes | -9.88° |
| Altair | +8° 52′ 06″ | yes | yes | -8.87° |
| Betelgeuse | +7° 24′ 25″ | yes | yes | -7.41° |
| Unukalhai | +6° 25′ 32″ | yes | yes | -6.43° |
| Bellatrix | +6° 20′ 59″ | yes | yes | -6.35° |
| Procyon | +5° 13′ 30″ | yes | yes | -5.23° |
| Menkar | +4° 05′ 23″ | yes | yes | -4.09° |
| Alrescha | +2° 45′ 50″ | yes | yes | -2.76° |
| Mintaka | -0° 17′ 57″ | yes | yes | +0.30° |
| Sadalmelik | -0° 19′ 11″ | yes | yes | +0.32° |
| Alnilam | -1° 12′ 07″ | yes | yes | +1.20° |
| Yed Prior | -3° 41′ 40″ | yes | yes | +3.69° |
| Yed Posterior | -4° 41′ 33″ | yes | yes | +4.69° |
| Sadalsuud | -5° 34′ 16″ | yes | yes | +5.57° |
| Rigel | -8° 12′ 06″ | yes | yes | +8.20° |
| Alphard | -8° 39′ 31″ | yes | yes | +8.66° |
| Zubeneschamali | -9° 22′ 58″ | yes | yes | +9.38° |
| Baten Kaitos | -10° 20′ 06″ | yes | yes | +10.34° |
| Spica | -11° 09′ 41″ | yes | yes | +11.16° |
| Algiedi | -12° 32′ 41″ | yes | yes | +12.54° |
| Dabih | -14° 46′ 53″ | yes | yes | +14.78° |
| Sabik | -15° 43′ 30″ | yes | yes | +15.72° |
| Zubenelgenubi | -16° 02′ 30″ | yes | yes | +16.04° |
| Deneb Algedi | -16° 07′ 38″ | yes | yes | +16.13° |
| Algorab | -16° 30′ 56″ | yes | yes | +16.52° |
| Sirius | -16° 42′ 58″ | yes | yes | +16.72° |
| Dorsum | -17° 13′ 58″ | yes | yes | +17.23° |
| Gienah | -17° 32′ 31″ | yes | yes | +17.54° |
| Mirzam | -17° 57′ 21″ | yes | yes | +17.96° |
| Difda | -17° 59′ 12″ | yes | yes | +17.99° |
| Alkes | -18° 17′ 56″ | yes | yes | +18.30° |
| Castra | -19° 27′ 58″ | yes | yes | +19.47° |
| Armus | -19° 51′ 18″ | yes | yes | +19.86° |
| Nihal | -20° 45′ 34″ | yes | yes | +20.76° |
| Facies | -23° 54′ 17″ | no | yes | +23.90° |
| Spiculum | -24° 21′ 30″ | no | yes | +24.36° |
| Kaus Borealis | -25° 25′ 18″ | no | yes | +25.42° |
| Antares | -26° 25′ 55″ | no | yes | +26.43° |
| Aludra | -29° 18′ 11″ | no | no | +29.30° |
| Fomalhaut | -29° 37′ 20″ | no | no | +29.62° |
| Kaus Media | -29° 49′ 41″ | no | no | +29.83° |
| Ascella | -29° 52′ 48″ | no | no | +29.88° |
| Aculeus | -32° 15′ 12″ | no | no | +32.25° |
| Kaus Australis | -34° 23′ 05″ | no | no | +34.38° |
| Acumen | -34° 47′ 36″ | no | no | +34.79° |
| Menkent | -36° 22′ 12″ | no | no | +36.37° |
| Shaula | -37° 06′ 14″ | no | no | +37.10° |
| Lesath | -37° 17′ 45″ | no | no | +37.30° |
| Ankaa | -42° 18′ 22″ | no | no | +42.31° |
| Sargas | -42° 59′ 52″ | no | no | +43.00° |
| Suhail | -43° 25′ 57″ | no | no | +43.43° |
| Canopus | -52° 41′ 44″ | no | no | +52.70° |
| Achernar | -57° 14′ 12″ | no | no | +57.24° |
| Agena | -60° 22′ 23″ | no | no | +60.37° |
| Bungula | -60° 50′ 08″ | no | no | +60.84° |
| Acrux | -63° 05′ 57″ | no | no | +63.10° |
Sources (method)
- Swiss Ephemeris fixed-star catalogue
sefstars.txt(ICRS/Hipparcos-based positions, proper motions, magnitudes): https://github.com/aloistr/swisseph/blob/master/ephe/sefstars.txt — ecliptic longitudes computed for this vault with Astropy 8.0 (GeocentricMeanEcliptic, mean equinox of J2000.0 and of 2026-01-01) - Jean Meeus, Astronomical Algorithms, 2nd ed. (Willmann-Bell, 1998) — ch. 13 (coordinate transforms), ch. 47 (Moon, nodes, perigee/apogee)